Numerical modelling of railway ballast at the particle scale

The paper describes the development of a technique to simulate triaxial tests on specimens of railway ballast numerically at the particle scale and its validation with reference to physical test data. The ballast particles were modelled using potential particles and the well-known discrete element method. The shapes of these elemental particles, the particle size distribution and the number of particles (N = 2800) in each numerical triaxial specimen all matched closely to the real ballast material being modelled. Confining pressures were applied to the specimen via a dynamic triangulation of the outer particle centroids. A parametric study was carried out to investigate the effects on the simulation of timestep, strain rate, damping, contact stiffness and inter-particle friction. Finally, a set of parameters was selected that provided the best fit to experimental triaxial data, with very close agreement of mobilized friction and volumetric strain behaviour. Copyright (C) 2015 John Wiley & Sons, Ltd.

本文描述了一种在颗粒尺度上对铁路道砟样本进行数值模拟三轴试验的技术的开发，并参照物理试验数据对其进行了验证。道砟颗粒采用势颗粒和著名的离散元方法进行建模。这些基本颗粒的形状、粒度分布以及每个数值三轴样本中的颗粒数量（N = 2800）都与所模拟的真实道砟材料非常吻合。通过对外侧颗粒质心进行动态三角划分，对样本施加围压。进行了一项参数研究，以考察时间步长、应变率、阻尼、接触刚度和颗粒间摩擦对模拟的影响。最后，选择了一组与试验三轴数据拟合最佳的参数，其调动摩擦和体应变行为非常吻合。版权所有（C）2015约翰威立父子有限公司。